For the 1920 x 1080 material, you will definitely want a Sequence, that matches that. With an SD Sequence, you are throwing out ~ 75% of your resolution.
Exactly how you handle the SD material is up to you. Some users have liked the results from Red Giant's Magic Bullet Instant HD, but others did not find the results what they needed. Might be worth a trial run, with some of your SD footage.
Thanks for the post Bill , and the link to Red Giant. Taking a look at the software. Yup. I knew I'd done something wrong, but could not figure out what. I should NOT have had to resize my clips to fit the frame. It was the sequence. Once I knew what the issue was I was able to get help quickly and the problem is solved. I created a new sequence with the proper specs, copied and pasted everything in. The editing is easier, the images clearer and better to work with.
What I wish for now is for a way to lock a clip in time. Not being able to do this sucks.
Can you explain?
a way to lock a clip in time.
There might be methods to accomplish what you want already, though if not, then John T's link to the Feature Request (which it appears that you have used), might help get what you want in later releases.
Good luck, and please let us know how Instant HD works (or does not) for you. As I mentioned, it has helped many, but certainly not all users. Depends on what one needs and what they are starting with.